I tried typing "python-i whatsapp_xtract.py msgstore.db.crypt" and it worked! : D Thank youuu!! . But missing a lot of conversations that had been deleted in the whatsapp, for example, I talk a lot with a friend of December 25, 2011 but the conversation does not appear.
Note: the backup is from January 5, 2012
Are you missing a whole chat (with a certain friend) or are you just missing some (older) messages inside that chat? As to say, are the newer messages with that friend included?
Are the messages also missing in the Whatsapp app? Maybe they have been deleted somehow.